Apparatus for remote control bombing



58, 1953 D. s. FAHRNEY 2,649,262

APPARATUS FOR REMOTE CONTROL BOMBING Filed Oct. 24, 1945 2 Sheets-Sheet l INVENTOR OELMER 5. FAHl-IWE Y ATTORNEY Aug. 18, 1953 Filed Oct. 24, 1945 D. S. FAHRNEY APPARATUS FOR REMOTE CONTROL BOMBING 2 Sheets-Sheet 2 D ELEVATOR RAD/0 REGE/ VER SPOILER RIGHT AIL E RON INVENTOR DLMER$ FAHRNEY QWLW Arrows! Patented Aug. 18, 1953 "TENT APPARATUS FOR REMOTE 'UGNTROL BOIVIBING (Granted under Title 35,11. SwCOdB (-1952),

see. 266') 1 Claim.

My invention relates to a method of and apparatus for bombing by remote control. In accordance with the invention, bombing is accomplished by controlling a glider into a position near, or into collision with, a target and by then causing detonation of an explosive within the glider, destroying both the glider and the target. Apparatus is provided in the glider to perform the following functions: to permit efiicient and safe towing by a powered aircraft; to cause the glider to be self-stabilized when in free gliding flight; to permit radio remote control of the glider in free gliding flight; to convey to an operator .at a remote point by television an accurate indication of the visible objects in the field of view in front of the glider; and to detonate the explosive charge carried by the glidereither upon impact or upon receipt of a signal from the operator.

Using the apparatus mentioned, it is contemplated that in bombing operations the glider will take ofi in tow behind a powered airplane, will be towed to a position of suflicient altitude and proximity with respect to the target for the .target to be within the gliding range of the glider, and will then be released into free gliding flight. The pilot of the powered airplane, or other operator, will thereafter remain in control of the glider through radio remote control, a view of the scene in front of the glider being transmitted by a television transmitter in the glider to a receiver at the remote control point. Gyroscopic stabilizing equipment in the glider maintains it in stable flight, the equipment being so arranged that remote control signals are effective to reorient the gyrcscopes enabling the remote control operator to change the attitude and direction of flight as desired to cause the glider to strike or approach the target viewable by the operator in the picture tube of the television receiver. The operator may, by remote control, detonate the explosive in the glider as it flies near the target; but if not so detonated, an impact switch causes detonation whenever the glider collides with the target.

An object of my invention is to provide apparatus by which a target may be accurately bombed without danger to the controlling personnel from enemy action.

Another object of my invention is to provide a pilotless glider adapted to carry an explosive charge which may be suitably controlled while in tow and while in free gliding flight, and from which will be transmitted a picture of the view in front of the glider to permit remote control to conform with information which would otherwise be available only to an operator in the glider.

.I-Ieretofore, flying torpedoes and various types of 'bombshave "been suggested which were adapted for carrying by parent airplanes and some of which were adapted to remote control. None of these devices have "met with any practical success except .for "use in the indiscriminate bombing of large areas when accuracy was unimportant. 'The device according to my invention overcomes diflicu'lties inherent in former devices in that the operator who may be .far removed from the glider and targetis in constant possession of the information essential to accuracy of the operation", that is, he witnesses an exact reproduction of the'view in front of'the glider. He is at all times certain of the course of the glider, though both glider "and target may be completely obscured from him by distance, clouds, or the like. Another most important advantage of my device, and the bombing method made possible by it, lies in the fact that :a relatively heavy bomb load may be rapidly transported to the area of the target by an aircraft-not adapted to carrying bombs or other loads, as for instance, a fighter airplane. Apparatus hitherto known has not been capable of'this type of operation without considerable modification of the parent aircraft. In using my invention, it is necessary to provide in the parent aircraft only a simple towing hook near the tailor on the underbody, a television receiver, and agradio transmitter. All of these may be "installed readily and will have no adverse effect on the streamlining or normal operation of the airplane. Accordingly, "the parent airplane'is'immediately restored to full efiectiveness as a fighter airplane when the glider is released therefrom for free gliding flight.

The glider-according to my invention may be of a standard mass-'production'type available in quantity. The towing aircraft may be of any typepowerful enough to "tow a glider. A minimum of expensive, time-consuming alteration is required in the towing aircraft and glider used in my invention. The operation may be carried out readily by pilots with little special training and withoutdangerto the pilot or other personnel or equipment.

Other advantages and objects of the invention will appear from the following description taken in conjunction with the drawings, .in which:

Fig. 1 is a side elevation showing the normal relative position of a towing aircraft and towed glider in flight;

Fig. 2 is a side elevation showing the parent aircraft, glider, and target as they might appear after release of the glider from tow;

relative position of the glider and powered aircraft, the towing cable 2 will remain substantially straight, since the glider will be at a small angle below the horizontal from the towing aircraft, the angle being such that the upward force of the air on the towing cable will be just sufficient to support the towing cable. In practice, this angle has been found to be approximately 9 for a particular size of cable and a given air speed, although changing these or other factors will change the angle. If the glider flies higher or iower than at the desired angle below the towing aircraft, the towing cable will not be supported by the air to the extent necessary to maintain the cable straight. Accordingly, if the glider is relatively too high, the towing cable will sagforward, and if too low will bow upward, between the ends. The feeler I5 following the cable will point above a predetermined preferred direction (which may be approximately 9 as mentioned above) in case the glider is too low, or below the preferred direction if it is too high. Motion in a lateral direction of the feeler will be caused by a lateral misalignment of the glider and towing aircraft. Vertical feeler deflection is made effective through a control system later described in connection with Fig. 3 to cause deflection of glider elevators, and lateral motion is effective to cause deflection of glider ailerons and rudder. The theory of operation of the feeler and the specific construction thereof are more completely described in the copending application of Moulton B. Taylor, Serial No. 592,627, filed May 8, 1945, now Patent No. 2,432,548, entitled Automatic Control.

In Fig. 2, the glider I is shown in free gliding flight after release from tow behind parent airplane 3. The glider is shown gliding toward a target such as the ship I, which is within the field of view, approximately centered along the longitudinal axis or line of flight of the glider as indicated by lines I42, of the television image transmitter tube of the television converter unit IE3 mounted toward the nose of the glider. Television transmitter I44 connected to the converter unit Hi3 feeds a signal comprising scanning and equalizing impulses and the picture components to transmitting antenna I45 for transmission to a receiving antenna I46 and receiver I41 in the parent aircraft. An image of the target is impressed on the screen I48 of the receiver cathode ray tube which may be seen by the pilot, giving him the information necessary to proper control of the glider toward the target.

A set of ten switches I5I is provided in the parent airplane to enable the pilot to switch onto the carrier wave generated in a radio transmitter I52 any one or more of ten predetermined modulation frequencies, the modulated carrier being radiated from an antenna I53 to be received on receiving antenna I54 on the glider. The signals received at the glider are fed to a suitable receiver I55 and control the operation of selected.

relays dependent upon the modulation frequency. The relays cause operation of certain control apparatus for the glider as will be later described. An explosive charge is indicated in the glider at I56, having an impact detonator.

The control system for the glider is diagrammatically presented in Fig. 3 of the drawings. This system comprises a feeler rod I 5 for indicating the position of the towing cable, and camoperated switching mechanisms controlled thereby through suitable cables for selectively applyin electrical energy from a battery 35 to trim and servomotors which deflect control airfoils. These airfoils consist of the usual elevator 48, rudder I18 and aileron 95, and, in addition, a spoiler or airbrake 65. A separate reversible servomotor is provided for the deflection of each of the control airfoils; that is, one for the elevator, one for the rudder, one for the ailerons and one for the spoiler. For clarity, only one aileron is shown, although an oppositely acting. second aileron is, of course, provided. The servomotors may be electrically powered, or they may be vacuum or hydraulically powered with electric valves suitably arranged to give right or left rotation as required. Three gyroscopes I'II, I64 and 94 are provided for controlling yaw, pitch and roll, respectively. The stabilization axes of these gyroscopes may be changed through operation of trim motors 86 and NH, as later explained. A solenoid actuated double-throw switch I62 is utilized to transfer control from the feeler rod to radio remote control at the time of release of the towing cable.

The operation of the control system while the glider is in tow, in which condition switch I62 will complete a circuit from battery 35 through on-oif switch 36 and switch blade I63 to contact I64, is dependent upon feeler rod I5, since power is provided from contact I64 to energize each of the cam-operated switches mechanically connected with the feeler. When the parent aircraft is to the left of the longitudinal axis of the glider, feeler rod I5 is pulled by the towing cable toward the left, moving arm [1 forward, this motion being transmitted through cable I9 to arm I5 connected to cam member I1, both of which are rotatable about an axis I8, the rotation being in the direction to stretch tension spring I9. As cam member TI rotates about axis I8, switch 62 is closed, providing power from contact I64 through conductor I65 and the switch 82 to conductor I66 and terminal 88 of trim motor 86 to cause arms and I6! of the trim motor to rotate in a direction to effectively shorten cables 90 and I68, which are strung around free-turning, pulleys 29 and I69, respectively. This rotation will be in a clockwise direction as shown in the drawing. Current return from trim motor 86, and from each of the other trim and servomotors, is provided through a grounded connection (not shown). The rotation of arm 85, as described, pays out follow-up cable 84 to permit tension spring 63 to rotate flat plate Bil in the direction of.

explained in detail in theaforementioned application entitled Automatic Control will adjust the stabilization axis of gyroscope 94 by turning pulley 93 through the unwinding therefrom of cable 98, resulting in the closing of switch 99 to provide current from the battery through conductor IiiI to conductor I03 and terminal 98 of servomotor 92. The arm 9| of the servomotor moves in a direction to give down right-aileron, or leftward roll control to aileron 95 through cable 96. The motion of arm 9| provides a follow-up action by effectively lengthening cable S5, which rides over free-turning pulleys =8 and 89 to permit slight rewinding of cable 80 on pulley 93 under the influence of spring tension. The stabilization axis of gyroscope 94 is thereby returned toward neutral position, causing switch 99 to center and remove power from servomotor 92. Simultaneously, cable I68 has unwound from reel I10 of directional gyroscope I'H due to motion of arm I61 of trim motor 86, changing the stabilization axis of this gyroscope in a manner similar to that in which roll gyroscope Q I is affected. Switch I12 is closed in the direction to provide power from the battery through conducs tor I73 and through the switch to terminal I'M of servomotor I15. Arm I11 rotates in a direction shown as clockwise in the drawing to deflect rudder I'I8 to the left turn position through cable I'iS. Follow-up cable I68 is effectively lengthened by the motion of the rudder, running around free-turning pulleys Isl, I 82 and I59 to permit rewinding on pulley I'IIJ returning the stabilization axis toward neutral. The ailerons and rudder retain the deflected positions until the glider has started to respond. As the glider rolls toward the left, the switch 99 of gyroscope 94 closes the battery circuit to terminal 97 of servomotor 92 which causes arm ill to return aileron 95 toward the neutral or center position. Follow-up of this motion is provided through cable 98 which slightly unwinds from pulley 93 and returns the stabilization axis to a position to again center switch 99 and remove power from the servomotor. Similarly, as the direction of the glider changes, the gyroscope III provides power through switch I72 to terminal I76 of servomotor H5 which then returns the rudder toward neutral in the amount necessary to readjust the stabilization axis through unwinding of cable I68 from pulley I10. As the direction of flight of the glider is changed through the combined effects of the deflected rudder and the lateral component of the towing cable pull, the feeler I5 is returned toward the center, and arm I? moves slightly rearward paying out cable I9, which causes arm 15 to rotate cam I7 into the position to close switch BI and apply power through conductor I83 to terminal I of trim motor 86. The arms 85 and It? of the trim motor are rotated so as to decrease the prior effective shortening of cables to and IE8, resetting the gyroscopic system to return the glider toward normal straight flight by action of the trim motor and associated apparatus just described, the actions being now reversed. These automatic adjustments to the control airfoil setting will continue until the longitudinal axis of the glider is directly in line laterally with the towing cable from the parent aircraft. It will be seen that a rightward displacement of the towing aircraft from the straight-ahead position will cause feeler I5 to move to the right of center, paying out, cable I9 and setting the trim motor and gyrcscopic sys= tem for the controlof the rudder and ailerons .so

as to cause rightward yaw and roll of the glider,

the sequence of the operations of the control apparatus being the same but in reversed direction.

Vertical displacement of the towing aircraft from the desired angle above the horizontal from the glider will similarly result in the application of suitable correction controls. If the towing :aircraft is higher than the preferred relative positions, feeler I5 is raised, .paying out cable I8 through the rearward motion of arm I6, allowing tension spring 28 to pull arm in the direction shown as clockwise in Fig. 3 about an axis 21. Cam member 26, pivoted about the same axis, is secured to arm 25 and in response to this motion, rotates in a direction such that roller 33 of switch rides up on raised portion 34 of the cam, closing theswitch to provide power through conductor 31 and the switch to conductor 44 and terminal d5 of elevator servomotor 43. Power to terminal 45 is effective to cause arm 46 to pull cable It! and deflect elevator 48 into an upward or climb position. Follow-up is provided through cable 59 which is effectively lengthened allowing tension spring 5| to rotate plate 3| in the same direction as the original displacement of arm 25.

Since plate 3i carries switch 30, the roller 33 will roll off of the raised portion 34, opening switch so and taking power off of servomotor'43. Arm 25 carries extending portion to which is connected a control rod 58 through which actuation of spoiler is accomplished. Any upward or downward motion of feeler I5 from the preferred position causes rotation of arms 25 and 55 about pivot 21, and this motion is effective through rod 56 to rotatearm 58 and cam member El attached thereto to disengage switch arm 6| from contact 58 and engage contact 66 providing power through conductor I53 to servomotor 64 which is effective through arm I59 and cable B? to move the spoiler into on position. A suitable limit switch (not shown) is provided to disconnect conductor 53 from the servo-motor when the spoiler E5 is in a desired position of maximum displacement. The return of feeler I5 to the preferred vertical position, which may be substantially 9 from the longitudinal axis of the glider in level flight, as previously explained, will be effective to return cam member 51 into the position in which the switch roller engages the lower cam surface, providing current through contact 88 and conductor 82 to servomotor 84 which rotates arm 69 toward the off direction returning spoiler E5 to neutral streamlined position. A second limit switch (not shown) may be provided to disconnect conductor 62 from the servomotor when the spoiler has reached neutral to prevent further operation of the servomotor, it being understood that each limit switch is arranged to reconnect conductor 63 and 62, respectively, whenever the spoiler has been moved slightly away from either of the limit positions. These limit switches may be conveniently built into the servomotor 84, and similar limit switching arrangements may be provided in servomotors c3, 92 and I15 to prevent over-control of the elevator, aileron or rudder airfoils, respectively. The purpose of spoiler 65 is to increase the air drag of the glider to pull out of the towing cable any inconsequential bowing of the towing cable'to the end that elevator deflection of the glider will be accurately controlled by true deviations from the preferred relative position of the glider with respect to the towing aircraft.

As heretofore mentioned, the glider may be released from the towing cable by radio remote control actuation of a solenoid coil, which, in turn, triggers a releasable connection for the end of the towing cable. Solenoid I89, as shown in Fig. .3, is adapted to trigger a suitable release mechanism upon excitation by pulling cable I85 as the core of the solenoid is sucked in. A suitable coupling, such as insulated cable I89, may be utilized to cause blade I63 of switch I62 to disengage contact I64 and engage contact I60 to provide electric current from battery 35 through switch 36 and switch I62 to conductors I86 and I8! and through them to pitch trim motor I6I and pitch gyroscope I84, and relay contact I88, respectively, It will be apparent that disconnecting contact I64 will make cam-operated switches 29, 30, 8I, 82 and 59 ineffective to cause any deflections of the control airfoils. As a result, feeler I is completely disabled. Remote radio control is now effective to operate selectively trim motors 86 and I6I as desired. Terminals of switches operated by relays in th output of the radio receiver, later described in conjunction with Fig. 4, are indicated by the numerals 266, 281, 208, 299 and 2H), respectively; When the appropriate modulation frequency is received at the glider, a relay is operative to complete a circuit from the ungrounded battery terminal to terminal 296 to excite the coil of solenoid I89 to release the towing cable through tripping cable I85 and to throw switch I62 into the radio control position. Reception of another selected modulation frequency will be effective to connect terminal 291 to the ungrounded terminal of the battery, which will cause rotation of arm I96 or" trim motor I6l in the direction to effectively shorten control cable I9I. The control cable will be unwound from stabilization-aXis-adjusting pulley I92 of pitch gyroscope I84 in a manner similar to that for gyroscopes 94 and ITI. Switch blade I93 will immediately engage contact I94, providing current from the battery through conductors I86 and I95 through the switch conductor I96 and conductor 46 to terminal 45 of servomotor 43. The servomotor will rotate in the direction to provide up elevator control through cable 6?. Arm I99 of trim motor Itl will continue to rotate in the direction stated until reception of the particular modulation ceases. Assuming that, as will normally be the case, only a short burst of the modulating frequency has been received, the arm I90 will have moved a short distance. As servomotor arm 46 rotates in the up-elevator direction, cable I9I is paid out over suitable free-turning pulleys and pulley I9? on the trim motor arm to permit slight rewinding on reel I62. Motion ofthe servomotor arm will thus continu until the elevator has been deflected a sufiicient amount to pay out cable I9I to the extent required to set gyroscope I84 and open the contact between blade I93 and contact I94. t will be seen that because of the effective shortening of follow-up cable I9I, gyroscope I64 will be operative to maintain the glider in a new pitch attitude by selectively applying additional up-elevator control by closing contact I94, or by applying down-elevator control by closing contact I98, as required to satisfy the system at any moment. will persist as long as arm I 96 remains away from its centered position. When power is removed from terminal 297, by discontinuing the modulation frequency, the trim motor arm I99 is returned to center position by power provided through conductor I86 to centering terminal I59. Internal cam-operated switches associated with This new condition 1 terminal I59 cause right or left rotation as required until the arm I is in a centered position. Of course,.the centering control is over-powered by application of current through either terminal 201 or 208. Power to terminal 298 will cause the trim motor to effectively lengthen follow-up cable I9I which will readjust the system to provide an attitude of increased dive. The application of power to terminal 209, through energization of the appropriate remote control relay, is effective to energize terminal 88 of trim motor 86 which will caus effective shortening of cables 99 and I68 of the aileron and rudder control systems. As heretofore discussed, decreasing the effective length of these cables tends to establish a leftward roll and leftward rudder positioning of the glider through the adjustments to the stabilization axes of gyroscopes 94 and Ill, respectively. Applying current in response to another modulation frequency to terminal 2 I ll energizes'terminal 81 of trim motor 86 to provide rightward roll and rudder setting. Power to terminal 299 will not only energize terminal 88 of trim motor 96 but will also energize relay coil 22! to close a circuit from relay armature I99 to stationary contact I88. Similarly, energization of terminal 2II) will, in addition to energizing terminal 87 of the trim motor, energize relay coil 228 to engage armature 222 with stationary contact 22L The closing of either one of the two sets of relay contacts alone has no controlling effect while the other set is open, but simultaneous closing of both sets by the simultaneous transmission of two modulation frequencies to energize both terminals 299 and 2 III will result in the completion of a circuit from the battery through switch 36, contact I65 of switch I62, conductor I81, contact I38, armature {99, conductor 229, contact 22 I armatur 222 and conductors 223 and 224 to a centering terminal 225 on trim motor 86 and caging terminal 226 on gyroscope I'II. The trim motor will accordingly operate to a centered position which will remove any bank of the glider, through the action of gyroscope 94, and gyroscope I'II will be caged in the direction of flight of the glider at that time. Thereafter, the glider will be controlled by the gyroscope IH to maintain this direction of flight until further signals are received by transmission of appropriate modulation frequencies.

In operation to change the lateral course of the glider, an appropriate modulation frequency is transmitted to energize terminal 299 for a left turn or terminal M9 for a right turn. Prim motor 86 is operated in accordance with this signal to cause yaw and roll in the selected direction and to a degree determined by the length of time the modulation frequency is received. The yaw and roll continues until two modulation frequencies are received simultaneously to energize terminals 209 and 2H) together. The gyroscope III is then caged, and the trim motor 86 centered to allow the glider to return to even keel, the gyroscope thereafter being operative to maintain the newly established direction of flight. In practice, it will be found necessary to give the centering and caging signal shortly before the glider has reached the desired direction to give enough time for the control to become centered as the glider reaches the desired direction.

The gyroscopes for controlling yaw, pitch and roll in the preferred arrangement are of the type in which air under atmospheric pressure is permitted to enter the cases of the gyroscope to spin the rotors and. to operate air pick-off systems which cooperate with suitable Sylphons for actuation of the electric switches. A partial vacuum is maintained in the: caseof each gyroscope. through the provision of suitable vacuum connections shown in Fig. 3 as lid for gyroscope 94, H8. for gyroscope- III, and 2!!! for gyroscope I84. A vacuum Pitottube (not shown) may be provided to furnish the required vacuum as the glider attains substantial air speed after takeoff, or avacuum pump may be provided in lieu of a Pitot tube to furnish vacuum for the gyroscopes and to power the servomotors if vacuumoperated motors are used. A wind driven generator is provided as shown in Fig. 3 for charging the battery 35 during flight. The arrangement com-prises a direct current generator 239- driven by a windmill 23L mounted outside of the glider, through a belt 232'. The generator is connected so as to act as a motor at low airspeeds so that it may be used to drive through a mechanical coupling any vacuum or hydraulic pumps (not shown) for required operation of vacuum or hydraulic apparatus in the glider. Airspeed switch 233 is set" to remain open until the airspeed of the glider reaches a predetermined amount, which may be approximately '70 miles per hour. Below this speed, power is provided through conductor 23 i and manual switch235 to the generator. armature to cause it to run as a motor, field supply being. through a suitable resistor 23%. Above the predetermined. speed, switch 233 closes to energize relay coil 23'! to move relay armature 238 away from. contact 239 and into engagement with contact 240. This change in connections inserts a voltage regulator 2 into the generator field supply, and thereafter the windmill provides energy to drive the generator as a generator to charge the batteries and to power the vacuum and hydraulic pumps if such pumps are used. Current and speed regulators may be added to the generator system if required under special conditions. It will usually be desirable to include pressure regulating mechanisms (not shown) for vacuum or hydraulic systems.

In Fig. 4' is shown a radio receiver I 55 for use in the glider to receive radio signals from the transmitter in the parent aircraft. As heretofore stated, the transmitter is adapted to the transmission of a single radio frequency carrier wave selectively modulated with any one of ten different audible or super-audible modulating frequencies. It is also possible to transmit the carrier modulated with two or more of the ten modulating frequencies. The carrier wave received on antenna N54 is suitably amplified and detected in receiver I55. In the final stage of the receiver are frequency selective circuits suitably coupled to a series of relays, each circuit being tuned to one of the ten modulation frequencies and so coupled as to operate a single relay in response to the reception of the appropriate modulation frequency. In lieu of a coupling arrangement, the actuating coil of each relay may comprise a portion of the tuned or frequency selective circuit on which the operation of the relay is dependent, Upon excitation resulting from reception of one of the modulation frequencies, the appropriate individual relay is operative to close a contact from the ungrounded terminal of battery 35 to one of the terminals EM, 252, 203, 204, 205, 208, 261, 298, 209 and 2m. Two or more contacts may be closed simultaneously upon reception of two or more modulation frequencies. When transmission and reception of any modulation frequency is stopped, the individual relay excited by that frequency drops out. Each relay is arranged to actuate mechanism, such as control mechanism, in the glider. One relay is connected so as to energize in response to one of the modulation frequencies a solenoid coil, I89 in Fig. 3, by supplying battery power to terminal 206', the solenoid being operative to trigger a release catch on the towing. cable connecting hook through cable I85 so as to allow the towing cable to pull free of the glider. The ring 26 at the tip of the feeler is also arranged to release the towing cable as the end of the cable is pulled up to the ring. The towing cable connecting hook and the ring on the tip of the feeler are more completely described in the copending application entitled Automatic Control previously mentioned. Certain others of the relays connected into the receiver output circuit are arranged to produce right or left yaw and roll of'the glider, or up'or down pitch, and to accomplish any desired additional functions, such as to armor' detonate the explosive, or to drop parachute flares. It will be apparent that the pilot at the transmitter, by selecting a particular modulation frequency of the transmitted wave, may cause the towing cable to bereleased from the glider, and may thereafter produce right or left turn and bank, or dive or climb, of the glider by selecting other frequencies as appropriate.

The apparatus described is particularly adaptable to the accurate bombing of specific targets or small areas from aircraft. The method contemplated by this invention comprises the towing of an explosive-carrying glider by a small powered aircraft, the glider being controlled while in tow by feeler I5 and the associated mechanism shown in Fig. 3. This mechanism is capable of maintaining the glider in a predetermined position relative to the towing aircraft as shown in Fig. 1, despite low visibility, turbulent air, and considerable maneuvering of the towing aircraft. Upon reaching a position with respect to the target from which the glider can be made toglide tothe target, the pilot of powered aircraft 3 may transmit by transmitter I52 a signal suitably modulated to close contact 206 in the output circuit of radio receiver I55. As explained in connection with Fig. 3, this will result in the release of the glider from the tow ing cable and will disable feeler I5 from further glider control. In this condition, the glider will be maintained in a stable flight attitude by the action of the three gyroscopes 94, III and I 84 and their associated equipment. The towing cable release and disabling of the feeler portion of the control system by the excitation of solenoid I89 is simultaneously operative to energize circuits sensitive to radio remote control of the flight attitude through radio receiver I 55. Accordingly, the pilot may select one or more of ten modulation frequencies for transmission, utilizing the bank of switches I5I in Fig. 2 to apply desired modulation frequencies. Accordingly, the attitude of flight of the glider is under the control of the pilot of powered aircraft 3. To enable intelligent and accurate control, television transmitting equipmcnt including converter unit I 43, transmitter M4, and antenna I on the glider are effective to transmit a signal modulated by suitable impulses to provide on the television receiver screen M8 in the powered aircraft an image of the objects appearing within the field of view in front of the glider shown as being bounded by lines M2 in Fig. 2. It is desirable to launch the glider, as heretofore described, after such time as it has been found possible to bring the target, such as vessel Ml, within the field of view of the television transmitter tube and to thereafter by radio remote control cause the glider to maintain a collision course with the target. As the glider approaches the target, the image thereof continuously increases in size, increasing the accuracy of the operation. In the meantime, the towing aircraft may have flown away to a safe distance to avoid anti-aircraft fire from the target or other enemy installations, and the glider may be completely obscured from view. However, the accuracy of the operation will not be impaired. A suitable detonator is provided within the glider to cause the explosion of the charge I56 whenever the glider is abruptly stopped, or the charge may be exploded by remote control whenever a particular modulation frequency is transmitted. It may be desirable to explode the charge above the target as, for instance, when scattering incendiary missiles.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claim rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claim are therefore intended to be embraced therein.

The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

What is claimed is:

In a towed glider adapted to be controlled directly when towed and to be controlled remotely when in free gliding flight, the combination comrising adjustable control surfaces for controlling the attitude of the glider, means coupled to each of said surfaces for adjusting the position thereof, a towing cable for towing said glider, feeler means couplin said cable to the glider, means responsive to the attitude of said feeler means for actuating said adjusting means to maintain the glider in a predetermined position with respect to said cable when in towed flight, and radio remote control means for actuating said adjusting means independently of said feeler responsive means, said remote control means including means responsive to a predetermined signal from a remote location for simultaneously releasing said tow cable, disabling said feeler responsive means and rendering said remote control means operable to actuate said adjusting means in response to other predetermined signals from said remote location.

DELMER S. FAHRNEY.

References Cited in the file of this patent UNITED STATES PATENTS OTHER. REFERENCES Television News, March-April 1931, pages 10, 11, 75, 76.

Publications: The Washington Evening Star of May 23, 1930, page D-12, and Oct. 27, 1939, page A-14. 

